Lug screw for construction forms



Aug. 19, 1969 w. H. oDELLQsR., ET-"AL 3,462,114

ALUG SCREW FOR cfnIs'l'Ruc'lION FORMS I Filed Nov. 21, 1966 Hal l '2Flez NvENToRs w/IILDEN H. O'DELL, SR.

' WALDEN H. O'DELL, JR.- 22 ,BY y v y FIGi g s PRIOR ART i ATTORNEYSUnited States Patent O 3,462,114 LUG SCREW FOR CONSTRUCTION FORMS WaldenH. ODell, Sr., 2118 Victor St., St. Louis, Mo. 63104, and Walden H.ODell, Jr., 2595 Cheshire, St. Louis, Mo. 63119 Filed Nov. 21, 1966,Ser. No. 601,279 Int. Cl. E09g 17/06; F16b 35 04 U.S. Cl. 249-195 3Claims ABSTRACT OF THE DISCLOSURE This invention pertains to an improvedlug screw for construction forms, particularly for forms used in theconstruction field when pouring foundation walls, and the like.

In the construction field after a concrete footing has been poured andset, wooden form sheets are erected in parallel vertical rows and areinterconnected by a series of tie-rods which are secured at the endsadjacent the outer surfaces of the forms. The wooden form sheets areprovided with spaced horizontally set straps and the tierod ends areheaded at the straps. Locking keys are then put in position tointerconnect the straps and tie the form sheets together. The lockingkeys are pivotally mounted on the form sheets by lug screws and otherlug screws on adjacent form sheets are provided so. that notches in thelocking keys can engage the other lug screws.

The problem which has existed for some time with wooden form sheets isthat the lugs screws quickly loosen up or pull out which renders theform sheets useless. In many instances the prevailing lug screws must betightened up so that eventually the heads are pulled into the woodbreaking the wood fibres and permitting water rot to set in. Also it isa problem that the lug screws eventually twist loose and cannotthereafter be tightened. A further problem is that the lug screws aremade with the usual right hand threads which promotes loosening when thelocking keys are hammered loose at the time of form sheet removal.

It is an object of this invention to provide an improved lug screw thatovercomes the problems prevailing with current types of lug screws.

Another object of this invention is to provide an improved lug screwthat can 4be used as an original component of form sheets or may be usedto replace the older types of lug screws as the latter are rendereduseless.

A further object of this invention is to provide an improved lug screwwith means which will accurately locate itself in the form sheet, willprovide means whereby excessive tightening can be prevented, and whichcannot be loosened during the disengagement of the locking keys.

Other objects of this invention will be-more particularly set forth inthe following description of a preferred lug screw, reference beingdirected to the accompanying drawings, wherein:

FIG. 1 is a fragmentary elevational view of a plurality of form sheetsset in position on a suitable footing and interconnected by lockingkeys;

FIG. 2 is a sectional view of the form sheets prior to pouring of theconcrete, the view being taken at line 2-2 in FIG. 1;

3,462,l 14 Patented Aug. 19, 1969 FIG. 3 is an enlarged fragmentary viewof a locking key and lug screws of this invention;

FIG. 4 is a sectional view taken at line 4--4 in FIG. 3;

FIG. 5 is an enlarged view of the improved lug screw showing detailsthereof; and

FIG. 6 is a view, similar to FIG. 5 of a prior art type of lug screw.

With reference to FIGS. 1 and 2 of the drawings, it can be seen that theform sheets 10 are set in vertical rows on a suitable footing 11, andthe parallel rows of ,form sheets 10 are secured against spreading by aplurality of tie-rods 12. Each form sheet is constructed of wood whichis cut to very accurate measurements as to length, width and thicknessso that accurately dimensioned poured concrete walls can be erected onthe footings 11. As may be seen, the form sheets 10 have a series ofstrap 13 secured in spaced relation to extend widthwise of each formsheet. The straps 13 are arranged so that they align horizontally, andthe adjacent ends of the straps 13 are interconnected by locking keys14.

Each locking key 14 is formed of a suitable length of strap material(FIG. 3) with a plurality of side open notches 15, 16 and 17, and with atransversely extending slot 18 at one end. The locking key 14 ispivotally secured by its slot 18 on a form sheet 10 by a lug screw 19',and one of the notches (in this case the outermost notch) 15 is engagedon a second lug screw 19a. The remaining notches 16 and 17 are providedto straddle the end of a tie-rod 12, depending on whether the tie-rodend is locate in one form sheet or the adjacent form sheet. In thepresent case (FIG. 3) the tie-rod end 20 is located in notch 16, but itmight be located to fall into notch 17. When properly set into positioneach locking key engages the lug screws 19 and 19a which, in turn, areengaged in the straps 13. Thus a continuous band is established from oneform sheet to another for resisting in tension the load of the concretein the space (FIG. 2) between rows of such sheets.

It is the prevailing practice to install the locking keys 14 at the sameends of the form sheet straps as shown in FIG. 1, and to pivot the keyscounterclockwise into position so that a few blows from a hammer willset them in final position. When it is time to remove the form sheets 19the worker will hammer the locking keys 14 from below to pivot themloose in a clockwise direction. This action occurs with some tensionload on the keys 14 so that the male portion of screws PA of the typeshown in FIG. `6, having the normal right hand threads 21 on the malemember 22 and matching threads 23 in the socket of the female member 24,will rotate and partially separate due to the friction forces acting onthe head 25 of the member 22. Also in the prevailing type of lug screwsPA the outer surface of the female member 24 is provided with twistedflutes 26 the more firmly to hold this member against rotation in thewood of the form sheet when threading up on the male member 22. However,the lug screw PA is not made with any means to prevent over tighteningbecause the threads 21 can be screwed up for the full thread length andnot bottom in the socket of the female member 24. The tendency alwaysis, when the lug screw PA is loose, to turn the head 25 more tightly andthis action draws the head 28 into the form sheet (the head 25 beingheld by shoulder 29 on the strap 13 in fixed position) breaking thelibres and setting up the conditions for water to enter and cause rot.As the wood rot continues the utes 26 no longer hold and the femalemember can rotate and become permanently loose. The locking key ispivotally mounted on the shoulder 29 so that it may pivot, but when thelug screw PA is tightened the shoulder is drawn tightly against thestrap 13 and the locking key is partially held against pivotingmovement. 'Ihis is so because there is no provision for holding a setdistance between head and head 28. The drawing of head 28 into the woodis objectionable for the reason that it produces an enlarged dimple inthe form sheets on the concrete side of the form sheets which leaves anunsightly mark in the nished wall.

The improved lug screw'19 of FIG. 5 overcomes the problems inherent withlug screws PA in a uniquely simple manner. It can be seen that theimproved lug screw 19 has a female member 30 formed with a head 31having a screw driver slot 32 therein. The shank surface of member 30 issmooth, and the socket is provided with left hand threads 33 in itsouter portion and with a counter bored recess 34 therebeyond. Thecooperating male member 35 is formed with a wrench engaging head 36having iiats of a thickness to provide substantial wrench faces 37. Itis especially important to form the head 36 with wrench engaging flats37 having a substantial thickness or increase in area as compared withthe ordinary lug screw head 25 shown in FIG. 6. A shoulder 38 isprovided for pivotally supporting a locking key by its slot 18, and theshank is provided with left hand threads 39 to engage the threads 33 infemale member 30. An extension 40 on the threaded shank 39 is providedto t into and bottom on recess 34 of the female member 30 so that whenthe members 30 and are fully threaded up there is established a fixeddistance between heads 31 and 36, thereby limiting the amount ofdraw-down of the lug screw members 30 and 35 so that there is avoidedthe problem of sinking the head 31 into the form sheets.

The foregoing description relating to the lug screw 19 applies equallyto lug screws 19a and it will not be necessary to describe the latter.

It is now believed clear in what manner the improved lug screw 19 isuniquely new and different from the prior art type of lug screw, and itis the intent to cover the improved lug screw as broadly as possible inthe appended claims.

What is claimed is:

1. A lug screw for construction forms comprising: a pair of cooperatingmembers engaged in a construction form from opposite sides; one of saidmembers having a head, a threaded socket and a smooth outer surface onthe socket; the other said member also having a head, a pivot formingshoulder adjacent said head, and a threaded shank extending outwardlyfrom said shoulder to engage with said threaded socket, said pivotforming shoulder having a diameter larger than said threaded shank; and

means on said pair of members limiting the distance between said headsupon threading said members together, said distance limiting meansincludes a counterbore in said socket of lesser diameter than saidthreaded socket and an extension on said shank of lesser diameter thanand adapted to bottom in said counterbore.

2. In combination with a plurality of adjacent construction form sheets,each having a plurality of tension straps secured thereto and lockingkeys pivotally mounted thereon by lug screws to swing into engagementwith other lug screws on adjacent form sheets, the improvement in saidlug screws wherein each lug screw comprises: a pair of` cooperatingmembers engaged in the form sheets from opposite faces; one of saidmembers having a countersunk head and an internally threaded socket; theother of said members having a wrench engaging head, a pivot formingshoulder adjacent said wrench engaging head to freely engage a lockingkey, and an axially extending threaded shank adjacent said shoulder toengage in said threaded socket; and means on said pair of memberseffective to limit the distance between said heads upon threading saidmembers together to prevent obstructing the free engagement of thelocking key, said distance limiting means includes a counterborc in saidsocket and an axial extension on said shank adapted to bottom in saidcounterbore.

3. In the combination of claim 2 where the locking keys swing in apredetermined circular direction out of engagement with lug screws, theimprovement wherein the threads of said socket and on said shank are ofthe opposite hand to said predetermined circular direction of swing ofthe locking keys.

References Cited UNITED STATES PATENTS 1,644,018 10/1927 Hull 85-4 X1,890,725 12/1932 Echols 2,898,659 8/1959 Shoemaker 249-195 X 3,055,0769/ 1962 VanHelder et al 24945 3,115,804 12/1963 Johnson 85-4 FOREIGNPATENTS 442,935 9/ 1912 France.

J. HOWARD FLINT, JR., Primary Examiner U.S. Cl. X.R.

